Tubing anchors

ABSTRACT

A tubing anchor apparatus used in conjunction with downhole pump systems for securing production tubing to a well casing. The tubing anchor is provided with a longitudinally extending cutout formed between two movable gripping elements which cooperate with the inside peripheral wall surface of the casing to form an unobstructed tunnel therethrough so as to permit a probe to be run downhole through the tunnel thereby enabling the formation underlying the anchor to be logged. Guide means provided on the upper extremity of the anchor enables the probe to be guided into the tunnel entrance.

rreenii OR s anntan United States Patent [1 1 1111 3 800 871 Watson Apr. 2, 1974 1 TUBING ANCHORS [76] Inventor: Billy Ray Watson, Box 756, Examinepjfm LePPmk Monahans, Tex 79756 Attorney, Agent, or Firm-Marcus L. Bates 22 Pl d: M 4,1 72 I 1 ay 9 57 ABSTRACT 21 A 1. N 250,435 l 1 PP 9 A tubing anchor apparatus used in COIIJUI'ICUOH with downhole pump systems for securing production tub 1 Cl ing to a well casing. The tubing anchor is provided 16 with a longitudinally extending cutout formed between [51] Int. Cl E211) 47/00, EZlb 23/00 two movable gripping elements which cooperate with [581 Field 01' Search 166/216, 217, 315, 250 the inside peripheral wall surface of the casing to form an unobstructed tunnel therethrough so as to permit a [56] R f r n s C t d probe to be run downhole through the tunnel thereby UNITED STATES PATENTS enabling the formation underlying the anchor to be 3,454,091 7/1969 Page, JR 166/217 logged. Guide means provided on the upper extremity 1100,53] 8/1963 166/216 of the anchor enables the probe to be guided into the 3,454,092 7/1969 Page, Jr. 166/217 tunnel entrancel,O66,000 7/1913 Crumpton.. 166/216 1,547,025 7 1925 Callahan 166/216 5 Cla'ms, 9 Drawmg Flgures PATENTED APR 2 I974 SHEET 1 OF 2 TUBING ANCHORS BACKGROUND OF THE INVENTION In a downhole pump assembly having a reciprocating sucker rod attached thereto, it is necessary to anchor the lower extremity of the production tubing in proximity of the pump so as to prevent the tubing from reciprocating within the well bore in response to the action of the pump jack. From time to time, for geological purposes, it is desirable to log the borehole. In order to log the formations underlying the tubing anchor, it has heretofore been necessary to remove the sucker rod, the downhole pump, and usually the tubing along with the tubing anchor. Such an undertaking is costly and often is the major economical reason for not carrying out a survey on the borehole.

It is therefore desirable to be able to log the portion of the borehole underlying a tubing anchor on a pumped well without undergoing the expense and loss of production occasioned by the removal of the pumping apparatus contained within the well bore.

SUMMARY OF THE INVENTION This invention relates to improvements in tubing anchor apparatus for anchoring the tubing string of a downhole pump assembly within a borehole. The tubing anchor includes an elongated body adapted to be connected into the tubing string and having spaced apart gripping elements thereon which can be forced into engagement with the interior of the casing of the well bore. A longitudinally extending extending cut-out forms an unobstructed tunnel through the apparatus, through which a probe can be lowered on the end of a wire line.

Guide means form the upper extremity of the anchor apparatus and guide the probe into the tunnel entrance. The gripping elements can be actuated by utilizing the hydrostatic head contained within the tubing string, or alternatively, the elements may be mechanically actuated by manipulation of the tubing string.

A sub located at each extremity of the body provides means by which the anchor can be located above or below the seating nipple of the pump assembly. The subs form a portion of a flow path which extends through the body, with the axial center line of the flow path being eccentrically located relative to the axial center line of the main body of the apparatus.

Accordingly, a primary purpose of this invention is the provision of improvements in tubing anchors which enable the portion ot a borehole underlying the anchor to be logged without the necessity of removing the anchor from the borehole.

Another object of the invention is to provide a method for logging a borehole without removing the pump assembly or the tubing anchor therefrom.

A further object of this invention is to disclose and provide a mechanically actuated tubing anchor which cooperates with the borehole casing in a manner to form an unobstructed tunnel through which a probe can be lowered on a wireline.

A still further object of this invention is to provide an improved tubing anchor which has guide means and a tunnel associated therewith so as to enable a probe which is lowered on a wireline to be guided into the entrance of the tunnel, through the anchor, and into the portion of the borehole underlying the anchor.

Another and still further object is to provide a hydraulically or mechanically actuated tubing anchor having radially spaced apart gripping elements arranged thereon with a longitudinally extending cut-out formed therebetween which enables a probe to be passed therethrough thereby enabling the lower extremity of the borehole to be logged without disturbing the sub-surface pump equipment.

These and various other objects and advantages of the invention will become readily apparent to those skilled in the art upon reading the following detailed description and claims and by referring to the accompanying drawings.

The above objects are attained in accordance with the present invention by the provision of a combination of elements which are fabricated in a manner substantially as described in the above abstract and summary, and the method for using the anchor apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatical representation of a crosssection of the earth showing a borehole disposed therein and with the present invention operatively associated therewith;

FIG. 2 is an enlarged cross-sectional view taken along line 2--2 of FIG. 1;

FIG. 3 is a fragmentary side elevational view of part of the apparatus seen in the foregoing figures;

FIG. 4 is a fragmentary view disclosing various important features of the apparatus seen in FIGS. 1-3;

FIG. 5 is a broken top plan view which discloses some of the apparatus seen in the foregoing figures;

FIG. 6 is an enlarged fragmentary cross-sectional representation taken along line 6-6 of FIG. 5;

FIG. 7 is an enlarged detail of part of the apparatus seen in FIG. 6;

FIG. 8 is a broken part cross sectional view which discloses part of the apparatus seen in FIG. 6; and,

FIG. 9 is a part cross-sectional view of a modification of the apparatus disclosed in FIGS. 5-8.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a borehole 9 extending through a hydrocarbon producing formation 10 which underlies the surface 11 of the earth. Production tubing 12 is generally enclosed within a casing and connected to outflow line 13 in the usual manner.

A pump-jack, not shown, reciprocates sucker rod 14 which actuates a downhole pump assembly located on a seating nipple and disposed within the tubing string at either 15 or 15, the specific location being a matter of choice.

A tubing anchor 16 is provided with subs 17, 17 with the subs providing the means by which the anchor can be flow connected to the production string at a location either above or below the pump assembly. Gripping elements are provided as part of the anchor and may be disposed in a manner as illustrated at either 18 or 118, as may be desired.

A probe 19 is suspended from a wire line 20 and has been run downhole within the casing annulus and past the tubing anchor, so as to enable the portion of the borehole underlying the anchor to be logged.

Looking now to thedetails of the remaining figures, the tubing anchor is seen-to include a main body having a circumferentially extending fixed gripping element 21 which is spaced apart from adjacent circumferentially extending movable gripping elements 18, 18.

The difference in the diameters of the subs and the main body of the anchor apparatus provides a circumferentially extending shoulder 22 at the upper terminal end of the main body. The shoulder is placed at a substantial acute angle relative to the longitudinal axis of the main body. This novel design expedient forms a guide means so that a probe lowered into contact with the sloped shoulder will be guided in a downward direction until it arrives within the entrance 24 of tunnel 23. The tunnel preferably is made in the form of a longitudinally extending U-shaped cut-out which cooperates with the inner peripheral wall surface of the casing to form an unobstructed longitudinally extending passageway through which a probe can travel.

Moreover, it will be noted that the axial center line 109 of the main body is eccentrically positioned relative to the axial center line 117 of the subs.

In one preferred form of the invention, cylinder 25 is located within enlarged area 116 of the main body and reciprocatingly receives in sealed relationship therewithin piston 26 having the illustrated seal means disposed thereabove. Connecting rod 27 is slidably received through a bushing 28. The free depending end of the connecting rod is provided with an enlargement 29 which bears against an uppermost surface 30 of a movable gripping element. The lower depending end 31 of the element is engaged with a biasing means which, for purposes of illustration, is disclosed as being in the form of a spring 32. Cavity 33 is formed within the main body and receives the spring therewithin.

Port 34 flow connects chamber 35 with the axial passageway 17'. The axial passageway connects together subs 17, 17 in fluid flow relationship. Port 36 exhausts fluid from the portion of the cylinder underlying the piston.

Each movable gripping element has a coextensive outwardly directed flange member 37 which is slidably captured in a reciprocating manner within a T-slot 38. Side walls 39 of the element extend radially outwardly from the body and terminate in the form of vertically spaced apart horizontally arranged teeth for gripping the side wall of the casing in high friction relationship when extended into contact therewith.

Where deemed desirable, spring 132 can be concentrically arranged about the connecting rod with the spring biasing the piston in an upward direction. T-slot 40 slidably captures enlargement 29 therewithin so that the gripping element follows the piston, thereby eliminating the spring 32 and cavity 33.

In the embodiment of FIG. 9, the spaced apart gripping elements are mechanically actuated between the retracted and anchored position. As seen in FIG. 9, the gripping elements are forced radially outward of the main body by the action of the illustrated cones. A drag device enables the cones to be forced towards or away from one another by rotating the production tubing in the usual manner.

OPERATION In operation, there will generally be a single pump, located at either 15 or 15. The tubing anchor is run downhole on the end of the tubing string and set. In the embodiment of FIGS. 5-8, as the pump effects hydrostatic head within the string, fluid flows through port 34, into chamber 35, thereby forcing the piston in a downward direction. This action forces the wedged shape gripping elements into gripping action relative to the casing wall. As the gripping elements radially expand into engagement with the wall, fixed gripping element 21 engages a third contact point of limited area located on the casing wall, whereupon the anchor is rigidly but removably affixed to the interior of the casing so long as a hydrostatic head of a sufficient value is present in the tubing string.

In the embodiment of FIG. 9, the gripping elements are set by turning the production string about its axial axis. The presence of the drag device maintains the lower cone member fixed relative to the casing wall, causing the spaced apart cones to be screwed towards one another, thereby forcing the gripping elements in an outward direction and into contact with the casing wall with a tremendous force because of the mechanical advantage presented by the wedge and screw threads. The mechanically actuated anchor apparatus is sometime preferred over the hydraulically actuated apparatus in view of the consequences brought about by an inadvertent parting of the production string in close proximity of the tubing anchor.

When it is desired to log the well, the probe is run downhole on any suitable support means such as a wire line, whereupon the lowermost surface of the probe contacts the guide means causing the probe to guidably slide down the inclined surface and into the entrance of the tunnel. Since the tunnel is unobstructed, the probe is free to pass through or along the side wall of the tubing anchor and continue downhole to the bottom of the borehole, thereby enabling a log to be made of the length of the well without the expensive necessity of pulling the rods, pump, tubing string, or the anchor.

It is considered within the comprehension of this invention to utilize other apparatus for setting the gripping elements, such as taught in US. Pat. No. 2,765,855, for example.

The present invention is rugged in construction, the costs are comparable to anchors of the prior art, and the present anchor apparatus can be substituted for tubing anchors of the prior art. The present invention also provides a new method for logging a producing pumped well.

I claim: 1. A tubing anchor apparatus for anchoring the tubing of a downhole pump system within a borehole comprising:

an elongated main body including means by which said body can be connected into a tubing string, said body having means forming radially spaced apart outwardly directed gripping elements thereon, means mounting one gripping element for movement in a radially outward direction relative to said main body; means forming a longitudinally extending unobstructed passageway through an outer marginal portion of said main body which forms a continuous U-shaped passageway along the entire length of the anchor apparatus so as to enable a probe to be lowered through said passageway on a wire line;

means forcing said one gripping element in an outward direction so as to cause each gripping element to engage the inside peripheral wall surface of the borehole;

said means by which said body can be connected into a tubing string includes a sub connected to the upper terminal end thereof; said sub having a diameter smaller than said main body so as to form a shoulder therebetween; said shoulder being downwardly sloped towards said passageway so that a probe lowered into contact with said shoulder will be guided in a downward direction into said passageway;

the axial center line of said sub being eccentrically arranged relative to the axial centerline of said main body, said one movable gripping element being disposed within a portion of said main body which is opposed to said sub.

2. The apparatus of claim 1 wherein there is included three said gripping elements, one said gripping element being fixed relative to said main body; two said gripping elements being movable relative to said main body;

said passageway being located between said two said gripping elements.

3. The apparatus of claim 2 wherein said main body includes means forming a flow passageway therethrough, said means for forcing said one gripping element includes a cylinder formed within said main body, a piston reciprocatingly received within said cylinder and forming a chamber therewith, means forming a port for enabling fluid to flow from said flow passageway into said chamber; and means connecting said piston to said one gripping element so that reciprocating movement of said piston forces said one gripping element to move radially relative to said main body.

4. The apparatus of claim 1 wherein said main body includes a cylinder, a piston reciprocatingly received within said cylinder and forming a cylinder chamber therewith, a source of pressure flow connected to said chamber, means connecting said piston to said one movable element, means slidably mounting said one movable element so that when sufficient pressure is effected in said chamber, said piston strokes and moves said one movable element radially outward into engagement with the inside wall of the borehole;

and means forming a flow path for produced fluid to flow through said body and into said sub.

5. Method of logging a borehole underlying a downhole pump wherein the pump is connected to a tubing string with the tubing string being affixed to the borehole wall by a tubing anchor in set positon, comprising the steps of:

l forming an unobstructed longitudinally extending U-shaped cut-out within the tubing anchor;

2 forming the upper portion of the tubing anchor into a guide means so that a probe when lowered into h bo shp t w be uid 'QIQ th a a y:

3 arranging a flow path through the tubing anchor which has an axial axis which is placed eccentric with respect to the tubing anchor;

4 placing the cut-out of step (1) in the portion of the tubing anchor which is opposed to the flow path of step (3);

5 attaching the tubing anchor to the wall of the borehole so that a longitudinally extending passageway is jointly formed by the inside wall of the borehole and the U-shaped cutout;

6 running a logging probe downhole into the borehole on the end of a wire line;

7 lowering the probe through the passageway of step (5) so as to enable the borehole underlying the anchorto be logged. V v AW 

1. A tubing anchor apparatus for anchoring the tubing of a downhole pump system within a borehole comprising: an elongated main body including means by which said body can be connected into a tubing string, said body having means forming radially spaced apart outwardly directed gripping elements thereon, means mounting one gripping element for movement in a radially outward direction relative to said main body; means forming a longitudinally extending unobstructed passageway through an outer marginal portion of said main body which forms a continuous U-shaped passageway along the entire length of the anchor apparatus so as to enable a probe to be lowered through said passageway on a wire line; means forcing said one gripping element in an outward direction so as to cause each gripping element to engage the inside peripheral wall surface of the borehole; said means by which said body can be connected into a tubing string includes a sub connected to the upper terminal end thereof; said sub having a diameter smaller than said main body so as to form a shoulder therebetween; said shoulder being downwardly sloped towards said passageway so that a probe lowered into contact with said shoulder will be guided in a downward direction into said passageway; the axial center line of said sub being eccentrically arranged relative to the axial centerline of said main body, said one movable gripping element being disposed within a portion of said main body which is opposed to said sub.
 2. The apparatus of claim 1 wherein there is included three said gripping elements, one said gripping element being fixed relative to said main body; two said gripping elements being movable relative to said main body; said passageway being located between said two said gripping elements.
 3. The apparatus of claim 2 wherein said main body includes means forming a flow passageway therethrough, said means for forcing said one gripping element includes a cylinder formed within said main body, a piston reciprocatingly received within said cylinder and forming a chamber therewith, means forming a port for enabling fluid to flow from said flow passageway into said chamber; and means connecting said piston to said one gripping element so that reciprocating movement of said piston forces said one gripping element to move radially relative to said main body.
 4. The apparatus of claim 1 wherein said main body includes a cylinder, a piston reciprocatingly received within said cylinder and forming a cylinder chamber therewith, a source of pressure flow connected to said chamber, means connecting said piston to said one movable element, means slidably mounting said one movable element so that when sufficient pressure is effected in said chamber, said piston strokes and moves said one movable element radially outward into engagement with the inside wall of the boRehole; and means forming a flow path for produced fluid to flow through said body and into said sub.
 5. Method of logging a borehole underlying a downhole pump wherein the pump is connected to a tubing string with the tubing string being affixed to the borehole wall by a tubing anchor in set positon, comprising the steps of: 1 forming an unobstructed longitudinally extending U-shaped cut-out within the tubing anchor; 2 forming the upper portion of the tubing anchor into a guide means so that a probe when lowered into the borehole, will be guided into the passageway; 3 arranging a flow path through the tubing anchor which has an axial axis which is placed eccentric with respect to the tubing anchor; 4 placing the cut-out of step (1) in the portion of the tubing anchor which is opposed to the flow path of step (3); 5 attaching the tubing anchor to the wall of the borehole so that a longitudinally extending passageway is jointly formed by the inside wall of the borehole and the U-shaped cutout; 6 running a logging probe downhole into the borehole on the end of a wire line; 7 lowering the probe through the passageway of step (5) so as to enable the borehole underlying the anchor to be logged. 